This invention is directed to a simplified keyboard input assembly and, in particular, to a keyboard input assembly having a reduced number of wiring connections for rendering same particularly suitable for use with electronic wristwatches, calculators and combination wristwatch-calculators.
Heretofore, keyboard input assemblies for use with electronic calculators, wristwatches and the like, have taken on various forms. The most popular form utilizes a keyboard comprised of a plurality of manually operated switches, each switch producing a predetermined input signal. As an alternative to such keyboards, electronic matrix systems, wherein digital signals are utilized to produce the predetermined input signals, have been provided. It is noted however that both keyboard input assemblies have been found to be less than completely satisfactory in view of the particular nature thereof. For example, when an independent switch or key is provided for each input, wiring is required for each input switch or key, thereby preventing the number of wires from being reduced to a number less than the number of keys or switches provided. In electronic matrix input systems, wherein digital signals are utilized to produce the predetermined input signals, although the wiring can be reduced, when digital displays such as those formed of liquid crystals and the like are utilized, the digital signals are not compatible with the display, thereby requiring the complex circuitry be utilized to render same compatible. Accordingly, an improved keyboard input assembly, wherein a manually operated switch is provided for each input, and wherein the number of wires coupled to the manually operated swtiches can be substantially reduced, is desired.